This proposal is concerned with investigations of molecular interactions which are involved in the regulation of muscular contraction. Solution conformational dynamics of actin and troponin subunits will be studied by static and time-resolved fluorescence spectroscopy, using both labeled and unlabeled proteins. The interactions of the proteins with each other and with tropomyosin will also be studied. From these investigations and studies of the effect of myosin binding on the conformation of unregulated and regulated thin filaments information about conformational changes produced by these interactions will be obtained. Transfer of excitation energy will be used to study proximity relationship within the thin filaments. The transient kinetics of Ca ion binding to troponin C, the solution dynamics of the Ca ion-troponin C complex, and the effect of interactions with other proteins on these properties will be investigated by stopped-flow and pulsed nanosecond fluorimetry. From these studies information about transient conformations and changes of these conformations and about the regulation of contractile activity by these processes will be obtained. The fluidity of sarcoplasmic reticulum vesicles will be studied by analysis of the time course of both monomer and excimer emission of incorporated pyrene. These results are expected to enhance our general knowledge of contractility and take us one step closer toward the elucidation of the regulatory mechanism of muscle contraction.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR025193-08
Application #
3155274
Study Section
Biophysics and Biophysical Chemistry A Study Section (BBCA)
Project Start
1979-09-25
Project End
1987-08-31
Budget Start
1986-09-01
Budget End
1987-08-31
Support Year
8
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of Alabama Birmingham
Department
Type
School of Medicine & Dentistry
DUNS #
004514360
City
Birmingham
State
AL
Country
United States
Zip Code
35294
She, M; Dong, W J; Umeda, P K et al. (1997) Time-resolved fluorescence study of the single tryptophans of engineered skeletal muscle troponin C. Biophys J 73:1042-55
Dong, W J; Cheung, H C (1996) Calcium-induced conformational change in cardiac troponin C studied by fluorescence probes attached to Cys-84. Biochim Biophys Acta 1295:139-46
Censullo, R; Cheung, H C (1994) Tropomyosin length and two-stranded F-actin flexibility in the thin filament. J Mol Biol 243:520-9
Liao, R; Wang, C K; Cheung, H C (1994) Coupling of calcium to the interaction of troponin I with troponin C from cardiac muscle. Biochemistry 33:12729-34
Censullo, R; Cheung, H C (1993) A rotational offset model for two-stranded F-actin. J Struct Biol 110:75-83
Wang, C K; Liao, R; Cheung, H C (1993) Rotational dynamics of skeletal muscle troponin C. J Biol Chem 268:14671-7
Liao, R; Wang, C K; Cheung, H C (1992) Time-resolved tryptophan emission study of cardiac troponin I. Biophys J 63:986-95
Wang, C K; Liao, R; Cheung, H C (1992) Nanosecond study of fluorescently labeled troponin C. Biochim Biophys Acta 1121:16-22
Wang, C K; Mani, R S; Kay, C M et al. (1992) Conformation and dynamics of bovine brain S-100a protein determined by fluorescence spectroscopy. Biochemistry 31:4289-95
Cheung, H C; Wang, C K; Gryczynski, I et al. (1991) Distance distributions and anisotropy decays of troponin C and its complex with troponin I. Biochemistry 30:5238-47

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